The invention relates to a method of providing tracks on a substrate in accordance with a pattern by means of a printing technique, for example, a resist pattern, conductor pattern, insulator pattern, resistor pattern or a black matrix. The invention can be used, in particular, to provide tracks of an electroconductive material on a substrate of an electrically insulating material (for example on glass or ceramic plates in a flat display device, such as a plasma display or PALC display (plasma-addressed liquid crystal display)).
In general, metal tracks are provided on insulating plates for a flat display device in the following manner: a layer of a metal is grown on the entire plate. Subsequently, the tracks are screen printed using a resist. Screen printing is carried out as follows: a screen-printing screen of a metal or synthetic gauze (for example polyester) embedded in a photopolymer, a part of the photopolymer layer being removed in accordance with the desired pattern, is placed on the substrate (the surface to be printed). In a screen-printing operation a squeegee is passed over the screen-printing screen, thereby the paste (for example a resist) used for printing is spread. With the squeegee a pressure is exerted on the screen-printing screen so that said screen engages the substrate and the hydrodynamic pressure causes a specific quantity of paste to enter the apertures in the screen-printing screen. When the squeegee recedes, the screen printing screen comes away from the substrate and the paste is transferred from the screen-printing screen to the substrate. After the resist has been screen printed, it is cured (depending on the type, with heat, radiation or light). The metal which is not covered with resist is removed by etching, whereafter the resist is removed.
The conductive tracks on the insulating plates in a flat display device are very narrow and, depending on the type of display devices, extend along the wall of cavities or holes in the plates. To ensure that the tracks extending in said cavities or holes are properly formed, two printing steps must be carried out during the provision of the resist. In a first printing step, the resist is provided to form the flat sections of the tracks, and in a second printing step, the resist is provided to form the sections of the tracks extending along the walls of cavities or holes. A problem may also arise if the width of the tracks is of the same order of magnitude as the meshes of the gauze in the screen-printing screen. This will lead to deformation of the tracks.